package com.milo.map;

import org.junit.Test;

import java.util.HashMap;

/**
 * @author milogenius
 * @date 2020-04-13 17:43
 */
public class HashMapTest {

    @Test
    public void test1(){
        HashMap<Object, Object> hashMap = new HashMap<>();
        hashMap.put("1", 1);
        hashMap.put("2", 2);
        hashMap.put("3", 3);
        hashMap.put(null, 4);
        Object o = hashMap.get(null);
        System.out.println(o);
    }
}
